Traders have introduced various so-called “zero-lag” moving averages, claiming that they react instantly to market changes. A key feature of these averages is the assignment of negative weights to distant prices. Previous findings suggest that negative weights can reduce lag while preserving smoothness. This chapter examines their impact on trading rule properties, assessing whether zero-lag moving averages truly minimize delay. The analysis shows that while negative weights enhance responsiveness and smoothness, they do so at the cost of accuracy. Moreover, despite their name, “zero-lag” moving averages still exhibit delay and often overshoot, leading to temporary misidentifications of trend reversals. By systematically evaluating these tradeoffs, this chapter clarifies the practical limitations of zero-lag moving averages and their implications for trading strategies.